But some physicians contend that increased risk may be a mirage. Instead of causing deadly cancer, 5-ARIs may simply make the disease easier to detect, says Neil Fleshner, M.D., a urologist at Princess Margaret Hospital in Toronto and a professor of surgery at the University of Toronto. These drugs shrink benign prostate tissue, Fleshner explains, which may improve the odds that a biopsy needle will find a small, but serious, tumor. Fleshner prescribes 5-ARIs to some men who have elevated PSA levels, a family history of the disease and other factors that increase their risk for prostate cancer.
4. Exercise: Just do it anyway
Although the general health benefits of exercise are beyond doubt, several large studies have failed to show that it lowers the risk for prostate cancer. One possible explanation: Healthy men who work out a lot may be more likely to get tested for prostate cancer. "Because they're more likely to get screened, they are more likely to be diagnosed with early-stage prostate cancer," says Steven C. Moore, a researcher at the National Cancer Institute. That could mask any potential protective effect of exercise. In fact, Moore says, other research suggests that exercise may guard against lethal forms of prostate cancer.
5. More sex … or masturbation
Finally, there's evidence that men who have frequent sexual intercourse or masturbate often may lower their risk for prostate cancer, possibly because ejaculation cleans out cancer-causing compounds that can accumulate in the gland. A study involving more than 29,000 male doctors and other health professionals found that men who ejaculated at least 21 times a month cut their risk for prostate cancer by up to 33 percent compared with men who reported an average of four to seven ejaculations per month.
Timothy Gower is a freelance journalist who lives on Cape Cod and writes about health and medicine.